We shall investigate in depth rodent models of CJD agent variants derived from human Gerstmann-Straussler-Scheinker cases and from progressive infantile encephalopathies (so called "Alper's disease"). We have already transmitted several of these cases in our laboratory to rodents. In the existing animal models of these diseases we will focus on incubation time, infectious titer and variations in pathological sequelae. As well, DNA and RNA from both human material (CJD, GSS and AD) and variant CJD isolates in rodents will be prepared for investigation of pertinent host genetic studies and for later use with selected cDNA probes (see Projects IVB, V, VI).